Measurement of lipid turnover rate in HeLa cell by heavy water labeling

Abstract

Heavy water (2H2O) labeling is a stable isotope labeling method that has been developed to quantify in vivo dynamics of biomolecules such as proteins, DNAs and lipids. Change in mass isotopomer distribution by deuterium labeling enable calculation of biomolecules’ turnover rates. Here we describe an experimental strategy for measuring in vivo lipid turnover rate in HeLa cell by 2H2O labeling coupled with high resolution mass spectrometry. Lipids were extracted from HeLa cell grown in 5% (mol/mol) 2H2O enriched media at 6 time points between 0 and 48 hours of labeling. Lipid species of glycerophospholipids, glyceryl esters and sphingolipids were identified based on in-silico Lipidblast library. The turnover rate of lipids in HeLa cell was determined in a range of 0.02-0.1 hr-1.